Thyroid hormone metabolism: importance of deiodination, conjugation and side chain modification

Extrathyroidal deiodination of T4 is the most important route for production of bioactive T3. This occurs predominantly in the liver, catalyzed by the microsomal type I deiodinase, which is also responsible for most of the degradation of the inactive rT 3. The liver is furthermore essential for the conjugation of iodothyronines with sulfate and glucuronic acid. This thesis deals with the connection between the various biochemical pathways of thyroid hormone metabolism. A better understanding of those metabolic routes involved in the regulation ofT 3 bioavailability helps to clarify the changes in the thyroid hormone economy induced by pathophysiological conditions. The successive Chapters II-VIII roughly reflect the chronological order of my experimental studie

Notitie duurzaamheid in relatie tot het bodembeschermingsbeleid

Discussienotitie over inpassen van duurzaamheid in het bodembeschermingsbeleid. Wat is duurzaamheid en hoe kun je dit vormgeven/uitdrukken/bepalen in het beleid, en hoe kan het huidige bodembeschermingsbeleid hierop in de toekomst aansluiten (of omgekeerd)

An Automated Design-flow for FPGA-based Sequential Simulation

In this paper we describe the automated design flow that will transform and map a given homogeneous or heterogeneous hardware design into an FPGA that performs a cycle accurate simulation. The flow replaces the required manually performed transformation and can be embedded in existing standard synthesis flows. Compared to the earlier manually translated designs, this automated flow resulted in a reduced number of FPGA hardware resources and higher simulation frequencies. The implementation of the complete design flow is work in progress.\u

Soil biological quality of grassland fertilized with adjusted cattle manure slurries in comparison with organic and inorganic fertilizers

We studied the effect of five fertilizers (including two adjusted manure slurries) and an untreated control on soil biota and explored the effect on the ecosystem services they provided. Our results suggest that the available N (NO3- and NH4+) in the soil plays a central role in the effect of fertilizers on nematodes and microorganisms. Microorganisms are affected directly through nutrient availability and indirectly through grass root mass. Nematodes are affected indirectly through microbial biomass and grass root mass. A lower amount of available N in the treatment with inorganic fertilizer was linked to a higher root mass and a higher abundance and proportion of herbivorous nematodes. A higher amount of available N in the organic fertilizer treatments resulted in a twofold higher bacterial activity (measured as bacterial growth rate, viz. thymidine incorporation), a higher proportion of bacterivorous nematodes, a 30% higher potential N mineralization (aerobic incubation), and 25–50% more potentially mineralizable N (anaerobic incubation). Compared to inorganic fertilizer, organic fertilization increased the C total, the N total, the activity of decomposers, and the supply of nutrients via the soil food web. Within the group of organic fertilizers, there was no significant difference in C total, abundances of soil biota, and the potential N mineralization rate. There were no indications that farmyard manure or the adjusted manure slurries provided the ecosystem service “supply of nutrients” better than normal manure slurry. Normal manure slurry provided the highest bacterial activity and the highest amount of mineralizable N and it was the only fertilizer resulting in a positive trend in grass yield over the years 2000–2005. The number of earthworm burrows was higher in the treatments with organic fertilizers compared to the one with the inorganic fertilizer, which suggests that organic fertilizers stimulate the ecosystem service of water regulation more than inorganic fertilizer. The trend towards higher epigeic earthworm numbers with application of farmyard manure and one of the adjusted manure slurries, combined with the negative relation between epigeic earthworms and bulk density and a significantly lower penetration resistance in the same fertilizer types, is preliminary evidence that these two organic fertilizer types contribute more to the service of soil structure maintenance than inorganic fertilize

Dissimilar response of plant and soil biota communities to long-term nutrient adition in grasslands

The long-term effect of fertilizers on plant diversity and productivity is well known, but long-term effects on soil biota communities have received relatively little attention. Here, we used an exceptional long-lasting (>40 years) grassland fertilization experiment to investigate the long-term effect of Ca, N, PK, and NPK addition on the productivity and diversity of both vegetation and soil biota. Whereas plant diversity increased by liming and decreased by N and NPK, the diversity of nematodes, collembolans, mites, and enchytraeids increased by N, PK, or NPK. Fertilization with NPK and PK increased plant biomass and biomass of enchytraeids and collembolans. Biomass of nematodes and earthworms increased by liming. Our results suggest that soil diversity might be driven by plant productivity rather than by plant diversity. This may imply that the selection of measures for restoring or conserving plant diversity may decrease soil biota diversity. This needs to be tested in future experiment

Effective Crack-Propagation Resistance Under Monotonic And Cyclic Loading

Crack propagation under monotonic and cyclic loading was investigated in alumina-epoxy composite specimens, produced via a multi-step infiltration technique. Under monotonic loading, an increase in effective fracture toughness was observed, which was attributed to the development of a bridging zone behind the crack-tip. A similar increase in crack propagation resistance was observed under cyclic loading, though this was more difficult to quantify. This was achieved approximately using an adjustment based on the Paris-law relation. This adjustment approach is described in this paper, and is also applied to fatigue results for graded composite specimens, in which the increase in crack-growth resistance with crack-extension is accompanied by a spatial variation in intrinsic and extrinsic crack-growth resistance

Sleutelfiguren: Thorbecke (1798-1872)

Wie kent niet mr. J.R. Thorbecke, de grote grondwet hervormer (1848) en auteur van de eerste Provinciewet (1850) en Gemeentewet (1851)? In ieder geval niet de installateur van mijn badkamer, tevens eigenaar van de voormalige sigarenfabriek in de Herensteeg (naast eethuis La Bota), waar Thorbecke op kamers zat toen hij in Leiden studeerde